From 770cb0ba97974623808f04de8549b509779bb645 Mon Sep 17 00:00:00 2001
From: Guy Benoish <guy.benoish@redislabs.com>
Date: Wed, 19 Feb 2020 08:24:20 +0530
Subject: [PATCH] XGROUP DESTROY should unblock XREADGROUP with -NOGROUP

---
 src/t_stream.c                     | 2 ++
 tests/unit/type/stream-cgroups.tcl | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/src/t_stream.c b/src/t_stream.c
index 0f0f97a1d..900fa3a17 100644
--- a/src/t_stream.c
+++ b/src/t_stream.c
@@ -1850,6 +1850,8 @@ NULL
             server.dirty++;
             notifyKeyspaceEvent(NOTIFY_STREAM,"xgroup-destroy",
                                 c->argv[2],c->db->id);
+            /* We want to unblock any XREADGROUP consumers with -NOGROUP. */
+            signalKeyAsReady(c->db,c->argv[2]);
         } else {
             addReply(c,shared.czero);
         }
diff --git a/tests/unit/type/stream-cgroups.tcl b/tests/unit/type/stream-cgroups.tcl
index a59e168ef..072ed14d6 100644
--- a/tests/unit/type/stream-cgroups.tcl
+++ b/tests/unit/type/stream-cgroups.tcl
@@ -161,6 +161,15 @@ start_server {
         assert {[$rd read] == {}} ;# before the fix, client didn't even block, but was served synchronously with {mystream {}}
     }
 
+    test {XGROUP DESTROY should unblock XREADGROUP with -NOGROUP} {
+        r del mystream
+        r XGROUP CREATE mystream mygroup $ MKSTREAM
+        set rd [redis_deferring_client]
+        $rd XREADGROUP GROUP mygroup Alice BLOCK 100 STREAMS mystream ">"
+        r XGROUP DESTROY mystream mygroup
+        assert_error "*NOGROUP*" {$rd read}
+    }
+
     test {XCLAIM can claim PEL items from another consumer} {
         # Add 3 items into the stream, and create a consumer group
         r del mystream